A US intelligence portrait of the world in 2030 predicts that China will be the largest economic power, climate change will create instability by contributing to water and food shortages, and there will be a 'tectonic shift' with the rise of a global middle class.

The National Intelligence Council's Global Trends Report, published every five years, says the world is 'at a critical juncture in human history.'

The report, which draws in the opinion of foreign experts, including meetings on the initial draft in nearly 20 countries, paints a future in which US power will greatly diminish but no other individual state rises to supplant it.

'There will not be any hegemonic power,' the report says. 'Power will shift to networks and coalitions in a multi-polar world.'